Many methods and apparatus exist for decontaminating soil from chemicals, such as hydrocarbons. Common to these inventions are complex and elaborate means for achieving such decontamination by introducing heat to a targeted soil area. The most common method for introducing heat is through heating pipes or the like.
For example, U.S. Pat. No. 5,228,804 to Balch, teaches a method and apparatus for ex-situ remediation of hydrocarbon contaminated soil wherein a pile of contaminated soil is covered with a tarp. A plurality of pipe conduits are inserted into the pile. Decontamination is achieved by volatilizing contaminants through introduction of heated air by the pipe conduits and utilizing solar energy trapped by the tarp.
U.S. Pat. No. 4,834,840 to Capella, discloses an apparatus for managing ex-situ toxic and hazardous waste material containing distillable solvents or chemicals in which the waste materials are collected and introduced into solar dryers, wherein the more volatile solvent or chemical components are distilled and recaptured as byproducts. The apparatus includes a drying tray having a transparent cover such that heat is generated through absorbed solar energy.
U.S. Pat. No. 5,193,934 to Johnson et al., teaches an in-situ thermal desorption system utilizing perforated pipe buried in soil. This invention is directed to removal of organic contaminants whereby the surface of the soil is covered with an impermeable membrane to prevent migration of released vapors. A combustion source provides heat to the soil via the buried piping.
U.S. Pat. No. 5,213,445 to Ikenberry et al., discloses a system and method for remediation of contaminated soil which includes an ex-situ soil stack interspersed with hot air dispensing pipes and vapor extraction pipes. Removal of contaminants is achieved by introduction of the hot air to allow vaporization, and removal of vaporized contaminants through the extraction pipes.
Although each of the foregoing patents disclose devices and processes which are satisfactory for their intended purposes, none discloses a method or apparatus for decontaminating soil by means of solar energy in the manner that is claimed herein.